Hermit crabs are born in the ocean. A female tosses her eggs into the sea, with the strongest surviving to evolve into hermit crabs.
It is possible to breed hermit crabs in captivity, albeit rare. You will need to home a responsive female in a separate breeding tank. Replicate the ocean experience with a saltwater pool in this tank. Add a sexually active male and wait to see if the female responds. It may take a choice of partners before a female agrees to breed.
Do not adopt hermit crabs will the sole intention of breeding. This will regularly end in disappointment. If you manage to convince two hermit crabs to breed, then you’ve been rather fortunate.
Do Hermit Crabs Breed?
Hermit crabs do not reproduce asexually. A male and a female are required to mate. If the mating is successful, the female lays eggs in the sea.
Once these eggs are ready to hatch, the female tosses them into the ocean. Marine Ecology Progress Series explains that some hermit crabs climb trees to do this safely. From here, the baby hermit crabs are on their own.
Can you see the problem with breeding hermit crabs in captivity? No ocean means, in theory, nowhere to release her eggs. You can potentially trick females into leaving eggs in a pool of saltwater in an enclosure, but this can be really tricky.
Hermit Crab Breeding Process Explained
The breeding behavior of hermit crabs can vary, depending on the species. In most cases, though, it will follow the same parameters:
- Females release a pheromone that announces that she is ready to breed
- Males detect this pheromone and approach
- The male hermit crabs fight over who will complete the breeding
- One of the males wins out, and the female decides if she is still interested. If the female wishes it to be so, the hermit crabs mate
Hermit crab mating can resemble fighting to the untrained eye. It looks as though the male is attempting to drag the female out of her shell. In reality, hermit crabs mate within their shells to stay safe. Males have a large penis that ensures females can be inseminated without leaving the shell.
During mating, the male deposits spermatozoa into the gonopores of the female. These are two tiny holes above the third set of legs. If fertilized, the female carries eggs within her abdomen for around a month. Once released, the hermit crab life cycle commences.
Hermit Crab Life Cycle
Once eggs are cast into the sea, they explode. Thousands of tiny larvae, known as zoeae, emerge from these eggs. These zoeae float in the sea. Many of them will eat each other. Others become snacks for marine wildlife.
If the zoeae survive for around 60 days, they make their way to land. This commences the next stage of the life cycle. At this point, zoeae evolve into megalopae. A megalopa is roughly the size of a fingernail and resembles a spider or tiny lobster.
The megalopa life stage lasts around 30 days. After this, the megalopa burrows under the sand of a beach. During this period, it molts and evolves. When the megalopa surfaces, it is a junior hermit crab. It will seek a shell and begin its new life.
What is the Ideal Hermit Crab Breeding Age?
Hermit crabs do not experience menopause, so theoretically, they can breed at any age. Most hermit crabs are driven to reproduce while young, though. There are two primary explanations for this behavior.
Life is dangerous for hermit crabs. These delicate animals are at the bottom of the food chain. Hermit crabs can live for decades, but few are so lucky. This encourages hermit crabs to breed as soon as possible. They wish to keep their species alive.
Size is also a concern. The larger a hermit crab grows, the harder it becomes to find an appropriately-sized shell. Females, in particular, are wary of this. They need to find a large enough shell to accommodate an egg sac, but not so big that it impedes mobility.
How Often Do Hermit Crabs Breed?
Female hermit crabs will try to breed multiple times in their first year of life. Pregnancy freezes molting and growth cycles. The more that hermit crabs reproduce, the longer they will fit into small shells, which are easier to source.
Male hermit crabs, meanwhile, will breed as often is permitted. Hermit crabs are sociable and live in large groups. This means that wild male hermit crabs are rarely devoid of mating opportunities. These will be seized wherever possible.
Hermit crabs do not take active roles in raising their young but welcome more arrivals to a colony. For hermit crabs, there is safety in numbers. Ergo, the more hermit crabs breed, the more friends will be available to offer protection.
There is also a slightly more selfish reason for hermit crabs to breed regularly. Shells are in a constant short supply, especially as hermit crabs prefer to occupy vessels that once held another crab. When a hermit crab dies, another crab claims its vacant shell.
This means that they need a constant availability of shells. The more hermit crabs live in the area, the likelier this becomes. Current Biology describes this phenomenon as, “social dependence.”
Do Hermit Crabs Breed in Captivity?
For a long time, it was believed that hermit crabs never mated in captivity. It has now been shown this is possible. It requires a great deal of patience and good fortune, though. Mating remains rare – almost non-existent – among captive hermit crabs.
This is primarily due to the unfamiliarity of the environment. As discussed above, female hermit crabs rely up on ocean water. You will need to trick a female into thinking she is in the wild to inspire breeding.
Even then, it takes a particular set of circumstances. Females are fussy about choosing a mate. Males also need to be completely relaxed and devoid of stress and anxiety. If these criteria are met, you may yet successfully breed two captive hermit crabs.
How Do You Breed Hermit Crabs in Captivity?
As discussed, breeding hermit crabs in captivity is a challenge. If you adopt hermit crabs to breed them, disappointment is likely. Though on the plus side, this does mean you can keep hermit crabs of the opposite sex together in a shared aquarium. You don’t need to sex hermit crabs.
If you are going to attempt to breed captive hermit crabs, the circumstances must be just so. To stand any chance of success, the natural habitat must be replicated as much as possible. Remember, the female hermit crab will seek out saltwater for birth.
Let’s take a look at the step-by-step process of breeding captive hermit crabs. One last time – this may or may not be successful. The latter outcome is likelier. If you convince your captive hermit crabs to breed, you have encouraged a minor miracle of nature.
Create a Breeding Tank
The first thing you’ll need to do is set up a special breeding tank. Do not attempt to breed hermit crabs in their standard enclosure. You’ll need a specialist environment for this practice.
Pick up a 10-gallon aquarium to use as your breeding tank. Set this is up as you would a standard habitat for your hermit crabs. Keep it away and from direct sunlight or any draughts. Include the following in the habitat:
- A sturdy lid that cannot be easily lifted, or a weight on the top
- A humidity of 80% (and a hygrometer to measure this)
- A temperature of around 80 degrees Fahrenheit
- A minimum of six inches of substrate (sand or soil – ideally the former)
- Drinking water
- Climbing apparatus
- Hiding places
- Other toys for recreation
This must be a welcoming, comforting habitat. Throughout the molting process, there will always be at least two hermit crabs in the tank. Your chosen female will be ever-present. If there is to be any chance of the hermit crabs mating, they must be completely content.
Replicate Ocean Conditions
If your female hermit crab is going to be tempted to breed, you’ll need to recreate an oceanic environment. This means bringing the sensation of the sea to the breeding tank.
In addition to drinking water, you’ll need to create a mini ocean. This is where the female will deposit her eggs when the time comes. Until then, it will be used as a saltwater bath for the tank’s occupants.
Find a vessel that is large enough to act as a pool. This should be big enough for the hermit crabs to submerge in. Also consider that, if you successfully breed hermit crabs, thousands of eggs will be laid. This means there must be plenty of additional space.
Use filtered or bottled water in this pool, heated to between 72 and 80 degrees Fahrenheit. Never use tap water, as this is toxic to hermit crabs. The chlorine, in particular, will kill your pets.
Next comes the time to add salt. This must be marine salt, not table salt. Table salt contains iodine, which is dangerous to hermit crabs. You can pick up marine salt from an exotic pet store or online.
Once ready, apply this pool to the aquarium. Ensure that it is easy for your hermit crabs to get in and out. A ramp is the easiest way to achieve this. Alternatively, add vines or netting. These will provide the hermit crabs with something to grip as they enter and exit the water.
Change the water regularly, always ensuring it is salted before returning to the tank. The presence of saline water will go some way to convincing your female hermit crab to breed.
Choose Your Timing
You will improve your chances of successful breeding if you time your attempt appropriately. Wild hermit crabs do not have a breeding season. In captivity, it is believed that hermit crabs prefer to breed between February and August. June and July are likeliest.
If your female has recently completed a molt at the height of summer, so much the better. Females are most receptive to breeding at this point in their life cycle. You cannot control when hermit crabs molt. This will come down to the luck of the draw.
If you notice pre-molting signs in spring, start preparing a mating tank. Be prepared to move your female as soon as she is active again after concluding a molt. Do not attempt to breed her until she has destressed and rejoined her tankmates.
You may find males congregating around a female in a shared tank. This suggests she is ready for mating. As per Ecological Research, male hermit crabs show more interest in females that are ready to breed.
Identify a Female Hermit Crab
You will need to identify your female for breeding. As discussed, a young female (ideally 1 year or younger) that has just molted is optimum. Older females, or those who are yet to molt, are less likely to respond well to advances from males.
To check if a hermit crab is female and sexually mature, wait for her to emerge from her shell. Handle the crab several times until she is comfortable with this activity. Once you have gained the trust of the hermit crab, you can check her sex.
Once you know what you are looking for, it is simple to sex hermit crabs. Females will have the following physical characteristics:
- Smooth, hairless legs (males have hairier legs)
- Three feathery appendages on the left of the legs. These are used to protect and carry eggs once inseminated
- Gonopores above the third set of legs
Female hermit crabs are particular about choosing partners, so you will need to be patient. As discussed in the Journal of Crustacean Biology, mating depends upon the female being receptive. Males cannot force females to mate against their will.
Do not switch your female until all options of male partners have been exhausted. Hermit crabs do remember their tankmates. Your female may be open to mating but is awaiting the arrival of a preferred companion.
How Do Hermit Crabs Choose a Mate?
Hermit crabs will typically choose a mate based on size. As explained by Behavioral Ecology, males prefer females of comparable size where possible. Females, equally, often gravitate to a larger male. This suggests the crab will produce more valid eggs.
As mentioned previously, males that detect sexual reciprocity from a female guard her jealously. This will lead to males attacking each other. As per the Journal of Zoology, the female may lose interest in mating due to the delay.
All the same, the Journal of Ethology claims that some female hermit crabs enjoy inspiring such competition. This helps determine the dominant male in a colony. This should be your first choice of partner. Let this practice unfold in a shared aquarium, not the breeding tank.
Introduce a Male Hermit Crab
Bring your male into the tank. Sex your hermit crabs as you did with the female. You are looking for a sexually mature male. That means hairy legs and no gonophores. Males also have a disproportionately large penis, around half the length of their abdomen.
If a male is keen to mate, it will gently rock the shell of the female. What happens next depends on whether the female is interested. She will respond by emerging and mating will begin, or she will ignore the advances and remain in her shell.
If no mating occurs within 24 hours, remove the male and replace it with another. Female hermit crabs do not release pheromones for more than a few days at a time. Keep trying with different males. This is still no guarantee of success, but it improves the odds.
Checking for Pregnancy
A female hermit crab that has been successfully inseminated will make a beeline for her saltwater pool. This where she will lay her eggs. If you spot your female bathing after mating, step one is complete. Leave the male in the tank for company during the pregnancy.
Female hermit crabs gestate for around 30 days. During this time, you will spot a clutch of eggs on the left-hand side of your female crab’s body. Female crabs can produce anywhere from 800 and 50,000 eggs, depending on their size—the bigger the hermit crab, the more eggs.
Nowhere near this many eggs will become hermit crabs. You will not have that many mouths to feed. This is why females create so many eggs. This provides the greatest likelihood of propagation of the species.
These eggs will be the color of red bricks while they grow. As the 30-day gestation cycle comes to an end, they will start to fade to a dull gray. This means the eggs are ready to hatch. This is the moment of truth.
As discussed, in the wild, this is when a female would toss her eggs into the sea. This is not an option in captivity. This is why it is so critical that your female believes her saltwater pool is an ocean. If this is the case, she will drop her eggs in this body of water.
From here, the life cycle that we previously discussed will commence. The eggs will hatch, and you’ll have a range of baby crabs to care for. The female will not play any further role in the raising of her offspring. You can return her, and her mate, to the shared tank.
How to Raise Baby Hermit Crabs
Pat yourself on the back if your female hermit crabs lays eggs in her saltwater pool. You have already achieved more than many experts. Sadly, the job is only half complete. Keeping the offspring alive long enough to become pets is a full-time job.
As discussed, the zoeae of hermit crabs are numerous and tiny. So small that you may mistake them for bubbles in the saltwater. These zoeae must remain in saltwater for the first 60 days of their life.
Throughout this period, Darwinism will come to the fore. Your hermit crabs may have produced thousands of eggs, but many of the larvae will consume each other. Many more will die through lack of strength or unsuitable conditions.
The saltwater that houses these zoeae must be changed regularly. The larvae cannot survive out of the water, though. You’ll need to ensure that you have a regular source of water vessels to alternate. Be careful not to lose any zoeae while transferring them.
Use a pipette or syringe to drip-feed these zoeae. Live plankton is the ideal food source. Alternative options include powdered spirulina, marine infusoria, or marine copepods from an exotic pet store
Evolution into Hermit Crabs
The zoeae that survive will eventually crawl into the substrate of your tank. At this point, the animals start becoming land dwellers. Consider removing the saltwater pool and replacing it with a smaller, safer vessel of water for bathing.
During the megalopa stage, hermit crabs can eat frozen krill, crayfish, or shrimp granules. Alas, you will lose several more hermit crabs at this stage. Many will struggle to survive in captive conditions of heat and humidity. Some will also cannibalize others.
Offer plenty of small shells here. Even bottle tops are better than nothing. The more protection a megalopa has, the better its odds of survival. As mentioned, after 30 days, surviving megalopae will burrow, molt, and evolve into hermit crabs.
It’s up to what you want you to do at this stage. If your aquarium is large enough, and you trust the incumbent hermit crabs, these babies can live with your other pets. Alternatively, keep them in the mating tank until you consider them large enough to mingle safely.
Attempting to breed hermit crabs in captivity is not for the impatient. The success rate is low and requires a great deal of effort and preparation. Even then, baby hermit crabs are delicate and need round-the-clock care.